Constant tension control mechanism



Dec. 25, 1956 D. B. RUSH ETAL CONSTANT TENSION CONTROL MECHANISM FiledJuly 9, 1953 IN VEN TORS. DAL: Hus, fl/JZLMM SEW/V6519, J'OXIVa THOMAS6919/ flazvnzo .5. Waapx 5 AY'Y'O/F/VA'Y I: I I/ 4 V F 40 4---@ 4 nitedStat s Patent iice,

2,775,414 CONSTANT TENSION CONTROL MECHANISM Dale B. Rush and William E.Springer, Columbus, Ind, and John B. Thomas, Belmont, and Donald E.Woody, Medford, Mass., assignors, by mesne assignments, to

The Reliance Electric and Engineering Company, Cleveland, Ohio, acorporation of Ohio Application July 9, 1953, Serial No. 367,042 Claims.Cl. 242-75 The present invention relates to a drive for a storage rollfor flexible material, and the primary object of the invention is toprovide a mechanism which, in response to tendencies toward variation ina condition existing in a length of such material moving relative to theaxis ofsaid roll, such as, for instance, tension, will automatically?vary the speed at which such a storage roll is driven, either forwinding or for unwinding of the material, in

order to maintain such condition against substantial jects, ourinvention may be embodied in'the form illus trated in the accompanyingdrawings, attention being.

called to the fact, however, that'the drawings are illustrative only,and that change may be made in the specific construction illustrated anddescribed, so long as the scope of the appended claims is not violated.

Fig. 1 is an end elevation of one form of the control of the presentinvention, assembled with a beam let-01f mechanism, fragmentarily andsomewhat diagrammatically illustrated;

Fig. 2 is a side elevation thereof;

, Fig. 3 is an enlarged vertical section through a preferred form ofcombined variable speed and difierential mechanism which may be used inthe practice of our invention; and

Fig. 4 is a section taken substantially on the line 4-4 of Fig. 3.

Referring more particularly to the drawings, it will be seen that wehave shown a frame in which is journalled a shaft 11 upon which iscarried a storage roll 12. A mass 13 of flexible material is shown woundupon the roll 12; and the parts are shown at a time, in the cycle of thesuggested machine, very shortly after the initiation of an unwindingoperation. It will be seen that the material is led from the mass 13 ina section 14 which is always tangent to the elfective surface of themass 13 (sometimes referred to as the effective surface of the storageroll) and, after passing over a control element later to be described,extends in a run 16 to mechanism, suggested at 15, through which thematerial is forwarded at a constant lineal velocity to a point of use(not shown).

A trackway 17, which may comprise a pair of parallel, horizontal racks,as shown, is supported upon the frame 10 in a plane spaced from, butsubstantially parallel with, the axis of the roll 12, said trackwayextending in a direction transverse to said axis. Wheels 18, which maybe toothed cogs, as shown, for meshing engagement with the said racks,support an axle 19 upon said track- Patented Dec. 25, 1956 a way 17 formovement therealong; and a roller 20 is s'upported upon the axle 19 forfree rotation about the axis thereof. The roller 20 constitutes thecontrol element above referred to, sometimes called a bearing member.

5 As shown, the roller 20 may be the conventional whip iroll of a loom.

An arm 21 is mounted for oscillation about a fixed axis 22 whichpreferably coincides with the axis of the shaft 11. In the illustratedembodiment of the invention,

10 said arm is actually mounted upon a projection of said :ishaft; thearm being free, however,for'oscillation with respect to said shaft. The.arm 21 projects into'proximity with the trackway-17 and, at its outerend, is bifurcated to define a slot 23, elongated in the direction oflength of the arm, and freely receiving aprojecting end 55.? of the axle19. Thus, the 'roller is operatively connected to the arm 21, wherebymovement of said roller along the trackway 17 willbe accompanied byoscillation of the arm 21 about its journal axis22. A cable 24' 20 hasone end anchored to the-arm 21, passes over a pulley -35? 25, andsupports a weight 26, whereby said arm is yield-, the left-hand-end ofably biased to hold the roller 20 at the trackway-17.

It will be seen that the roller 20 bears against the inner surface ofthe material 14 withinthat sector which is w: defined between the pointof tangency of the section 14 with the effective surface of the roll,and a plane includin the axis of the roll 12 and normal to the run 16.

A shaft indicated at 27 is driven through suitable means 2;; wardingmeans 15. A sprocket 28 on the shaft 27 is connected, through a chain29, to drivea sprocket 30 on a shaft 31 of a control assembly indicatedgenerally by the reference numeral 32, Said control assembly isillustrated in detail in Figs. 3 and 4..

7 Within a frame or housing 33 is journalled. a first shaft 31. ,Asecond shaft 34 is journalled in said frame 33 upon an axis parallelwith the axis of the shaft .31; and a third shaft 35 is journalled insaid frame upon an axis aligned with the axis. of the shaft 34. A sungear 36 is :fixed on the shaft 34 and a sun gear 37 .is fixed on theshaft 35. A, differential housing or carrier 38 .isjour:

nalled to rotate upon the axis common to the shafts 34 and 35, andsupports planetary gears 39 meshing with the sun gear 36 (Fig. 4) andplanetary gears 40 meshing with the sun gear 37 and with the gears 39.

A sprocket 41 is fixed to the shaft 31, a

is fixed to the carrier 38,and a chain 43 provides affixedratio driveconnection bet'ween the sprockets 41 and 42.

The differential mechanism thus comprises a first input 1 element 38, asecond input element 34 and an output; element 35. If the shaft 34 andthe carrier 38 are driven at a common velocity and in the samedirection, the shaft 35 will be driven at the same velocityin the samedirection. However,-any reduction in the velocity of the carrier 38relative to that of the shaft 34 will result in a reduction in thevelocity of the shaft 3 5, until, when the velocity of the carrier38 isone-half that of the shaft 34, the shaft 35 will be held againstrotation. Any further 60 increase in the differential between thevelocities of the input elements will result in rotation of the shaft 35in the opposite direction. Thus, the speed and direction of' rotation ofthe output element 35 are measured by the differential between thespeeds of the input elements.

An expansible V-pulley, indicated generally'by the reference numeral 44,is mounted on the shaft 31, and'comon the shaft 34 and comprises a coneddisc 49 fixed to (not shown) at aconstant ratio with respecttothe forsprocket 42:

with the disc 46. A resiliently expansible V-pulley, indicated generallyby the reference numeral 48, is mounted 3 said shaft, a mating coned.disc 50 axially adjustable toward and away from the disc 49,. and aspring unit indicated generally by the reference numeral 51, ofconventional construction, tending always to press the disc 50resiliently toward the disc 49. V -belt 52" provides a drivingconnection between: the pulleys 44 and 48; and it will be seen that thisassembly constitutes a' variableratio. driving connection between theshaft 31 and the second input element 34 of the differential gear.

Upon a suitable pivot 53 within the frame 33 there is oscillably mounteda bell crank lever 54, one arm 55 of'which is formed as a yoke engagingthe bearing housing 47 on opposite sides of the shaft 31, and the otherarm 56 of which is disposed in the path of an actuator element 57. Saidelement 57 comprises a pin or rod reciprocablymountedin a wall of theframe 33 and provided with adjustable stop collars 58 and 59 limitingits stroke, said pin projecting outside theframe 33 fora purpose laterto become apparent.

' A reduction gear, indicated by the reference numeral 60, comprises aworm 61 drivingly connected to the output shaft 35 of the assembly 32-,and a worm wheel 62 mounted on a shaft 63 which projects from the gearhousing and externally carries a' sprocket 64 which,

through-a chain- 65, isconnected to, drive a sprocket 66 on the shaft11'.

The arm 21 includes, or carries, a projection upon which is-formed' acam surface 67 extending into cooperative engagement with the actuator57.

When a loaded storage roll 12'is mounted in the frame 10, the arm 21,under the influence of the weight 26, will be in its extremecounter-clockwise position, in which the roller 20 on the axle 19" willbe at the extreme lefthand end of. the track 17.. The end of thematerial on the roll will now be carried over the roller 20 and to theforwarding means 15, and thence to a point of use. When the forwardingmeans is energized, the shaft 27 will likewise be driven. The parts areso proportioned and designed that the carrier 38 will'thereby be drivenat a velocity sufiiciently less than that of the shaft 34 that the roll12 will be driven at an angular velocity such as to maintain apredetermined degree of tension in the run 16. As material is withdrawnfrom the mass 13,

the effective diameter of the roll. is decreased. Since the rollisturning, at a constant angular velocity, there is a tendency for thetension in the run 16. of material to increase. At the same time thepoint of tangency of thesection 14. withthe effective surface of themass 13 moves gradually toward the right as viewed in Fig. 2. Thecombined effect of. these two tendencies will. be to increase thehorizontal component of the force exerted upon the roller by thematerial, whereby the tendency of the weight 26 is overcome, and theroller 20 will be moved toward the right along. the trackway 17;Thereby, the arm 21- will be moved in a clockwise direction. The cam- 67is so designed. that, such movement of the said arm willpermit theactuator 57' to rise, thereby permitting the lever 54 to;move in aclockwise direction and permittingthe disc 4610 move away from the disc45, all under the influence, of the spring unit 51 which,.

as has been said, is constantly-tending to force the disc 50 toward the,disc 49, thereby squeezing the belt. 52.

outwardly between saiddiscs and pulling it more deeply between the discs45 and 46. The result of such adjustment, of course,.will be to reducethe speed of the input element 34, thereby. reducing the differentialbetween the speeds of the input elements 34 and 38, and increasingthe-speed of the output shaft 35 and of the roll 12.

This adjustment continuesprogressively, as the effective diameter of themass 13 (roll' 12) progressively decreases, to maintain constant tensionupon the run 16 which. is continuously forwarded, at a constant linealspeed, by the forwarding-means 15-.

It will be clear that the illustrated mechanism could be used, also, ina winding. operation. In such. a case, the forwarding means 15 would, ofcourse, move the material toward, instead of away from, the storage rollat a constant velocity; and the control mechanism would operate toreduce the angular velocityof the roll 11 progressively, under thedomination of variations, or rather tendencies toward variation, in thetension in the section 16 of the material. The roller 20 would moveprogressively from its dotted line position toward its solid lineposition to permit the arm 21 to. move in a. counterclockwise direction,during such winding operation.

The variable-ratio drive means, of course, comprises the pulley pair 44,48, while the constant-ratio-drive means comprises the sprockets 41 and42. It will be clear that the sprockets 41 and 42. with the chain 43are, in many respects, the equivalent of a pair of fixed-ratio pulleyswith a connecting belt; and the expression pulley pair, as usedin theappended claims, is intended to include-a pair of sprockets suchas 41and 42.

We claim as our invention:

1. Means for automatically controlling the rate of rotation of a storageroll for flexible material comprising, in combination with such a roll,alengthof flexiblematerial wound on said roll, means for forwarding saidmaterial substantially. in a plane at constant lineal ve locity, adifferential gear including a first input element, a second inputelement, and an output element, means connecting input elements tocontrol the speed of said output element in accordance with thedifferential between the speeds of saidinputelements, rotary meansdriven at a constant ratio with respect to said-forwarding means,constant-ratio drive means connecting said rotary means to drive saidfirst inputelement, variable-ratio drive means connecting said rotarymeans todrive said second input element, an" arm mounted for oscillationabout a fixed axis in a common plane with the axis' of said roll, meansoperatively engaging said arm andbearing against the innersurface ofsaid material: at a point within the sector defined between the currentpoint of tangency ofsaid material with the effective surface of saidroll and a plane including the axis of said roll and normal to the planeof movement of said material, means yieldably urging said arm away fromsaidnormal' plane and toward said current point of' tangency, meansconnecting said arm to vary the ratio of said variableratio drive meansin response to movement of'said' arm,

and means providing a driving connection between said material. wound onsaid roll, means for. forwarding said material at constant lineal'velocity, a differential gear including a first input element, a secondinput element, and an output element, means connecting said inputelements to control the speedof'said'output element in accordance withthe differential between the speeds of the input elements, rotary meansdriven at a constant. ratio with respect to said forwarding means,constant-ratio. drive means connecting said rotary means to drive saidfirst input element, variable ratiodrive-means connecting said rotarymeans todrive said second" input element, an arm mounted for oscillationabout the axis of said roll a trackway spaced from said axis; saidtrackway being disposed in a plane substantially parallelwith said axisand said trackway extending in a directiontransverse to the direction oflength ofsaid axis, a bearing member supported on said trackway formovement therealong, bearing against the inner surface of said' materialat a point within the sector" defined betweenthe current point saidbearing member being operativelyconnected with said arm, said arm beingyieldably biased away from said normal plane and toward said currentpoint of tangency, means connecting said arm to vary the ratio of saidvariable-ratio drive means in response to movement of said arm, andmeans providing a driving connection between said output element andsaid roll.

3. Means for automatically controlling the rate of rotation of a storageroll for flexible material comprising, in combination with such a roll,a length of flexible material wound on said roll, means for forwardingsaid material at constant lineal velocity, a differential gear includinga first input element, a second input element, and an output element,means connecting said input elements to control the speed of said outputelement in accordance with the differential between the speeds of saidinput elements, rotary means driven at a constant ratio with respect tosaid forwarding means, constantratio drive means connecting said rotarymeans to drive said first input element, variable-ratio drive meansconnecting said rotary means to drive said second input element, anelement movable oppositely to vary oppositely the drive ratio of saidvariable-ratio drive means, an arm mounted for oscillation about theaxis of said roll, a

trackway spaced from said axis, said trackway being disposed in a planesubstantially parallel with said axis and said trackway extending in adirection transverse to the direction of length of said axis, a bearingmember supported on said trackway for movement therealong, bearingagainst the inner surface of said material at a point Within the sectordefined 'between the current point of tangency of said material with theeffective surface of said roll and a plane including the axis of saidroll and normal to the plane of movement of said material, said bearingmember being operatively connected with said arm, said arm beingyieldably biased away from said normal plane and toward said currentpoint of tangency, means on said arm operatively engaging said actuatorto shift the same upon movement of said arm, and means providing adriving connection between said output element and said roll.

4. Means for automatically controlling the rate of rotation of a storageroll for flexible material comprising, in combination with such a roll,a length of flexible material wound on said roll, means for forwardingsaid material at constant lineal velocity, a differential gear includinga first input element, a second input element, and an output element,means connecting said input elements to control the speed of said outputelement in accordance with the differential between the speeds of saidinput elements, rotary means driven at a constant ratio with respect tosaid forwarding means, constantratio drive means connecting said rotarymeans to drive said first input element, variable-ratio drive meansconnecting said rotary means to drive said second input element, an armmounted for oscillation about the axis of said roll, a trackway spacedfrom said axis, said trackway being disposed in a plane substantiallyparallel with said axis and said trackway extending in a directiontransverse to the direction of length of said axis, an axle supported onsaid trackway for movement therealong, a roller supported on said axlefor free rotation about the axis thereof, said roller bearing againstand supporting the inner surface of said material at a point within thesector defined between the current point of tangency of said materialwith the eifective surface of said roll and a plane including the axisof said roll and normal to the plane of movement of said material, saidarm being formed with a longitudinally-extending slot and said axlehaving operative engagement in said slot, means yieldingly urging saidarm away from said normal plane and toward said current point oftangency, means connecting said arm to vary the ratio of saidvariable-ratio drive means in response to movement of said arm, andmeans providing a driving connection between said output element andsaid roll.

5. In a device of the class described, a frame, a storage roll forflexible material journalled in said frame, means on said frameproviding a trackway spaced from the axis of said roll and extendingtransversely relative to said axis, an arm mounted for oscillation aboutthe axis of said roll and extending into proximity to said trackway, awheeled axle supported on said trackway for movement therealong andoperatively connected to said arm, said arm being yieldably biased tohold said axle near one end of said trackway, a roller supported on saidaxle for free rotation about the axis thereof, said roller bearingagainst'said flexible material at a point between said roll and saidforwarding means and being supported thereby against the bias of saidarm, a differential mechanism mounted adjacent said roll axis andincluding a first input element, a second input element, and an outputelement, means connecting said input elements to control the speed ofsaid output element in accordance with the differential between thespeeds of said input elements, a driven shaft, constant-ratio drivingmeans connecting said shaft to drive said first input element,variable-ratio driving means connecting said shaft to drive said secondinput element, an actuator shiftable oppositely to vary oppositely theratio of said variable-ratio driving means, means carried by said armand operatively connected to shift said actuator upon movement of saidarm, and means providing a driving connection between said outputelement and said roll.

References Cited in the file of this patent UNITED STATES PATENTS2,175,551 Perry Oct. 10, 1939 2,581,328 Malcom Ian. 1, 1952 2,608,741Reeves Sept. 2, 1952 2,664,724 Lambach Jan. 5, 1954 FOREIGN PATENTS235,025 Switzerland Nov. 15, 1944

